MethodResolver results are cached in SpEL expressions, so changing the context at evaluation time has no effect [SPR-9495]

[spring-projects-issues]

Dave Syer opened SPR-9495 and commented

MethodResolver results are cached in SpEL expressions, so changing the context has no effect. It's nice that there is some control over MethodResolver in StandardEvaluationContext, but because the results are cached in the expression itself (deep in MethodReference so no options I can see to override), they only have an effect once. Users are confused because they set a MethodResolver which apparently is ignored when passed into an expression at evaluation time:

Expression expression = parser.parseExpression("...");
StandardEvaluationContext context = new StandardEvaluationContext();
context.addMethodResolver(new SpiffyMethodResolver());
assertTrue(expression.getValue(context, Boolean.class));
context = new StandardEvaluationContext();
context.addMethodResolver(new CrappyMethodResolver());
assertFalse(expression.getValue(context, Boolean.class)); // FAIL! (it's using the result from the old resolver)

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Affects: 3.1.1

Issue Links:

• SPEL and Enum variable resolution using wrong cachedExecutor [SPR-10452] #15085 SPEL and Enum variable resolution using wrong cachedExecutor

Referenced from: commits c5aa0d1, b7ff26a, baa698e, 6de67cc

[spring-projects-issues]

Juergen Hoeller commented

Fixed through only caching against the ReflectiveMethodResolver now, where we know that the returned MethodExecutor is stable and cacheable. It seems generally unsafe to make caching assumptions about any other MethodResolver.

Juergen